Army Special Forces veteran Randy Tipton isn't quite ready to say he feels like television's "Six Million Dollar Man." But his brand-new robotic foot represents a groundbreaking advance in prosthetics technology made possible by tens of millions of dollars the U.S. government has poured into research to "rebuild" service members who've lost limbs in Iraq and Afghanistan.

This week Tipton, 45, of Manvel, became the first Veterans Affairs patient in the nation to receive the iWalk PowerFoot BiOM. The high-tech prosthesis uses precision robotic engineering to propel each step and adjust to changes in speed and terrain.

"All other (prosthetic) feet are passive, meaning they may have a hinge to the ankle, but they aren't going to power you," Benveniste said. "This foot is an active foot."

The PowerFoot uses micro­processors, sensors, a motor and a carbon-fiber spring to replicate the action of the amputee's Achilles' tendon, ankle and calf muscle.

It comes with three batteries that last up to six hours each and links to Bluetooth, so Tipton can adjust the settings using his Droid smart phone.

The Power­Foot senses where it is in space, automatically adjusting to uneven ground like stairs or ramps, said Shane Namack, iWalk's vice president of sales.

"Also, it's reflexive, so the more he puts into it, the more energy he gets out of it," Namack explained. "Someone like Randy should be able to walk with the same energy expenditure as he did with two legs."

Herr is founder and chief technology officer of iWalk, a Massachusetts company he started in 2006 with venture capitalist funding.

Veteran skeptical at first

The PowerFoot is the first in a series of products that iWalk is developing to emulate — or even enhance - body movement through electro­mechanics, according to the company's website.

"War is unfortunate, but most advances in technology come during wartime," Namack noted.

The PowerFoot now is in limited market release for the Defense Department, the VA and a few select facilities across the U.S.

No retail price has been set, but Namack said such devices can cost $50,000-plus, compared to an average of $900-$2,600 for an advanced carbon-fiber prosthetic foot.

As a vet, Tipton got his PowerFoot free through VA.

At first, Tipton was skeptical of the PowerFoot. At 4½ pounds, it was even heavier than another prosthetic he had rejected because it was too exhausting to lift.

One step was all it took

From the minute he took his first step, though, Tipton was sold.

"First word I said was, 'Wow' - for real," he said. "I haven't been able to walk like that since before I lost my leg, so it was an instant 'wow.' I think I said 'wow' about 40 times."

Tipton said he used to feel like he was dragging his prosthesis, but "this one has its own power to it."

In recent years, researchers have created other so-called "bionic" limbs that use electronics and mechanics, but Benveniste said this is the only foot that's both biomimetic, meaning it mimics the natural human body function, and robotic, meaning it has a motor to replace the function of the muscles.

"I've had many people tell me in their saddest moments, 'I just want my leg back,' " he said. "This is about as close as you can get."